The phrase "as a reference category" is correct and usable in written English.
It is typically used in academic writing when referring to a certain group of items, people, or objects that provide a basis of comparison for other items, people, or objects. For example, "The researchers used historical paintings as a reference category to compare the compositions of modern artworks."
Index dummies represent selection indices of Deutsche Börse AG, using 'no index' as a reference category.
At the same time, as a reference category, the drug group "no relevant outpatient drug prescription" was selected.
Index dummies represent the selection indices of Deutsche Börse AG, using 'no index' as a reference category.
The regions in China were geographically divided into three areas: western region, central region, and eastern region, with western region as a reference category.
Whether or not respondents have housing problems was operationalized as a dichotomous variable (those with housing problems were treated as a reference category).14 (6) Family effect.
Interestingly, all economic branch dummies produce significant results but must always be interpreted alongside the primary sector (including mining, energy and the building industries) as a reference category.
We therefore employ index dummies capturing the respective share index in which firms are included, i.e., Dax, MDax, TecDax or SDax, using 'no index' as a reference category.
Another qualitative control consists of several industry dummies following the sector logic of Deutsche Börse AG, with the sector "Telecommunications" as a reference category.
When tension-type headache group is taken as a reference category, APOE ε2 gene was found to increase the odds of migraine by 2.31 (95% CI = 1.08 4.94; P = 0.01).
These rankings were used to create three dummy variables: (1) free countries (free countries = 1, used as a reference category); (2) partly free countries (partly free countries = 1); and (3) unfree countries (unfree countries = 1).
this group served as a reference category.
